1. Field of the Invention
This invention relates to novel derivatives of diaminomaleonitrile (DAMN). More particularly, this invention relates to N-.alpha.-cyanoalkyl compounds of diaminomaleonitrile represented by the formula (I) ##STR3## wherein R represents a straight or branched chain alkyl group having 1 to 4 carbon atoms or a phenyl group; to iminonitrile compounds of diaminomaleonitrile represented by the formula (II) ##STR4## wherein R is as defined above; and to processes for preparing the compounds of the formulae (I) and (II) above.
2. Description of the Prior Art
Hitherto, it was well known that a Schiff base formed between DAMN and an aldehyde represented by the formula (A) ##STR5## wherein R' represents an alkyl group or an aryl group can be reduced with sodium borohydride to form the corresponding N-alkyl- or N-aryl compounds represented by the formula (B) ##STR6## wherein R' is as defined above, as disclosed in R. N. Begland et al., J. Org. Chem., 39, 2341 (1974). However, the reaction of diaminomaleonitrile with acyl cyanides which belong to a chemical class different from aldehydes has not been reported previously. The different feature of the reaction between the reactions with aldehydes and with acyl cyanides is apparent from the fact that the Schiff base of the formula (A) has not been obtained from lower alkyl aldehydes but from aromatic aldehydes while the iminonitrile compounds of the formula (II) can be obtained readily from lower alkyl acyl cyanides as well as aromatic acyl cyanides. Moreover, the products of the present invention having the formulae (I) and (II) can be cyclized readily into pyrazine derivatives, but the cyclization of the compounds of the formula (A) gives imidazole derivatives and, in fact, no report has been found with respect to self-condensation of the compounds of the formula (B) to form cyclic compounds.